Identifying
potential targets for drugs that could
work against all corona viruses
The possible emergence of
vaccine- resistant SARS-CoV-2 variants, as well as novel corona viruses, makes
it important to find treatments that work against all corona viruses. Now, researchers
have analysed viral proteins across 27 coronavirus species and thousands of
samples from Covid-19 patients, identifying highly conserved
sequences that could make the best drug targets.
Drugs often bind inside
“pockets” on proteins that hold the drug snugly, causing it to interfere with
the protein's function. 3cientists can identify potential drug-binding pockets
from the 3D structures of viral proteins. Over time, however, viruses can mutate
their protein pockets so that drugs no longer fit. But some drug-binding
pockets are so essential to the protein's function that they can't be mutated,
and these sequences are generally conserved overtime in the same virus, and in
related viruses.
The researchers wanted
to find the most highly conserved drug binding pockets in viral proteins from
covid-19 patient samples and from other corona viruses, revealing the most
promising targets for pan coronavirus drugs.
The team used a computer
algorithm to identify drug binding pockets in the 3D structures of 15
3AR3-CoV-2 proteins. The researchers then found corresponding proteins in 27
coronavirus species and compared their sequences in the drug binding pockets.
The two most conserved“
drug gable” sites involved proteins(callednsp13 andnsp12 respectively) that are
involved in viral RNA replication and transcription. The researchers said novel
antiviral drugs targeting the catalytic site of the protein nsp12 are currently
in phase II and III clinical trials for Covid- 19, and that the RNA binding
site of nsp13 is a previously underexplored target that should be a high
priority for drug development.
Test predicts who is likely to be infected
with severe Covid
Researchers have developed
a blood test to predict which people
infected with Covid-19 are most likely to experience serious symptoms,
which could help health care workers
prioritise patients for hospitalisation and intensive care. To measure changes in blood biochemistry that occur with severe Covid-19,the researchers chose a technique called attenuated total
reflectance Fourier transform infrared spectroscopy (AYR-FYIR),which has been tested previously as
a Covid-19 di-agnostic tool.
Two regions of FYIR spectra from 128 patient plasma samples
showed small but observable differences between those with severe
and non-severe Covid-19. Using these data together
with clinical information about patients,
the researchers developed a statistical
model to predict Covid-19 severity.
They found that the best
predictor was whether the
patient had diabetes, followed by the two regions
in the FYIR spectra. Adding the FYIR data to the model improved the sensitivity
for detecting severe disease
in a different set of 30 patients from 41.2 % to 94.1%, it reduced the specificity from 84.6 % to 69.2 %, compared with the clinical factors alone. This means that the new test was more likely to identify severe cases, but it also had a higher rate of false positives.
Blood clotting may be
root cause of long Covid: study
A new study has reported
evidence that patients with long Covid syndrome continue to have higher
measures of blood clotting. The authors say this may help explain their persistent
symptoms, such as reduced fitness and fatigue. The study, led by researchers
from Ireland.
In long Covid syndrome, symptoms can last weeks to months after the initial infection has resolved an misestimates to affect millions of people worldwide. The researchers examined 50 patients with symptoms of long Covid syndrome to better understand if abnormal blood clotting is involved. They discovered that clotting markers were significantly elevated in the blood of patients with long Covid syndrome compared with healthy controls These clotting markers were higher in patients who required hospitalisation with their initial Covid- 19 infection, but they also found that even those who were able to manage their illness at home still had persistently high clotting markers.
NIH scientists develop faster Covid-lt test than RT-PCR
Science at the US National Institutes of Health (NIH) have developed a new sample preparation method to detect SARS-CoV-2.The
method by passes extraction of the virus' genetic RNA material, potentially reducing
test time and cost.
The method is the result of a collaboration among researchers
at the US. Standard tests
involve amplifying viral RNA to detectable levels
using a technique called RT- qPCR. But first, the RNA must be extracted from
the sample. Manufacturers of RNA extraction kits have had difficulty keeping up
with demand during the pandemic.
The researchers used an agent made by the lab
supply company Bio-Rad called’ Chelex 100 resin' to pre-serve SARS-CoV-2 RNA in samples for detection by
RT-qPCR. We used nasopharyngeal and saliva
samples with various virion concentrations
to evaluate whether they could be used
for direct RNA detection. The answer was yes, with markedly high sensitivity .Also, this preparation inactivated
the virus, making it safer for lab personnel to handle positive samples.
The team made their discovery by testing a variety of chemicals using synthetic and human samples to identify those that could preserve the RNA in samples with minimal degradation
while allowing direct detection of the virus by
RT-qPCR.
To validate the test, they collected
patient samples and stored them in either viral transport media, or the newly developed
chelating- resin buffer at the NIH Symptomatic Testing Facility. The samples in
viral transport media were tested by the Covid-19 testing team at NIH's
Clinical Center, using conventional RNA extraction and RT-qPCR testing. The
samples in the chelating-resin-buffer were heated and the viral RNA was, then,
tested by RT-qPCR. The new preparation significantly increased the RNA yield
available for testing, compared to the standard method.
Vaccine protection declining, suggest three CDC
studies
The US Centers for
Disease Control and Prevention (CDC) released three studies on that provided evidence that booster shots of the
Pfizer-BioNTech and Moderna coronavirus vaccines would be needed by all
Americans in the coming months. But some experts said the new research did not
support the decision to recommend booster shots for all Americans.
Taken together, the studies show that although
the vaccines remain highly effective against hospitalizations, the bulwark they
provide against infection with the virus has weakened in the past few months. It's
unclear whether the decline in protection against infection is the result of
waning immunity, a drop in precautions like wearing masks, or the rise of the
highly contagious Delta variant— or a combination of all three. “We are
concerned that this pattern of decline we are seeing will continue in the
months ahead, which could lead to reduced protection against severe disease,
hospitalization and death.
Citing the data, federal health officials
outlined a plan for Americans who received the two vaccines to get booster
shots eight months after receiving their second doses, starting September
20.But some scientists were deeply sceptical of the new plan. These data
support giving additional doses of vaccine to highly immunocompromised persons
and nursing home residents, not to the general public.
Boosters would only be warranted if the vaccines were failing to prevent
people from ending up hospitalized with Covid-19. Feeling sick like a dog and
laid up in bed, but not in the hospital with severe Covid, is not a good enough
reason.